Danny Boyle has confirmed he still hopes to reunite the cast of Trainspotting for a sequel, but he is waiting for them to age enough first.

The Oscar-winning director's 1996 cult hit featured Ewan McGregor, Ewan Bremner, Jonny Lee Miller, Robert Carlyle, Kevin McKidd and Kelly Macdonald. And Danny said he would like to make a follow-up film when the cast have reached "mid-life crisis" point.

He told movie blog Cinematical: "It will happen, I think. I mean, we'll approach them all again about it, but it will depend on what place they're all at. We have a very strong idea that it would be a wonderful thing to re-approach, to do again, when they have aged clearly into a mid-life kind of crisis, basically. They're not quite there yet, I don't think."

The film was based on Irvine Welsh's novel of the same name, and Welsh wrote a follow up, Porno, which Ewan McGregor has previously said he does not think would make an ideal film sequel.

Danny agreed: "He's right of course that the book, Porno, is not a great book in the way that Trainspotting, the original novel, is genuinely a masterpiece, I think, as a piece of writing. But we have been doing some work on it, and it's got potential for sure. And when the moment's right, I think we will approach it."

The Slumdog Millionaire director insisted a delay was necessary to make the characters relevant again.

He said: "It will be nice because I hope that the thing that will happen then is that it won't be just cashing in.

"This is an imaginative thing to look at these guys, who you kind of fell in love with and a whole generation fell in love with in a certain kind of way, and then you see them again and they've aged, just like we all do."